Wattmeter.



No. 838,784. PATBNTED DEC. 18, 1906. L. E. IMLAY.

WATTMETER.

APPLICATION I'ILED FEBJG, 1905.

THE u'ukms PETERS ca. WASHINOTDN. n. c.

UNITED STATES earner @FFTCE.

WATTNIETER.

Specification of Letters Patent.

Patented Dec. 18, 1906.

Application filed February 16, 1905. Serial No. 245,831.

To all w/wm it may concern.-

Be it known that I, LORIN E. TMLAY, a citizen of the United States of America, residing at Niagara Falls, in the county of Ni agara and State of New York, have invented new and useful Improvements in Wattmeters, of which the following is a specification.

My invention relates to wattmeters, and more particularly to wattmeters which are graphic, self-recording, and capable of measuring power delivered by single or polyphase alternating currents.

My invention is, furthermore, an improve ment upon the Wattmeter described, shown, and claimed in the copending application of Joseph Wills and myself, Serial No. 213,498, filed June 21, 1904.

Referring to the drawings herewith, in which like characters of reference indicate corresponding parts, Figure 1 is a plan view, partially diagrammatic, of my invention. Fig. 2 is a detail view in elevation on the line a; of Fig. 1 looking in the direction of the row.

1 1 and 2 2 2 2 are respectively the current-coils and potential coils of two singlephase wattmeters.

3 is the aluminium or copper disk, which constitutes the movable secondary element.

7 This movable secondary element 3 is mounted rigidly upon an oscillated shaft 4, which is supported in jewel-bearings 5 and 6. The jewel-bearings 5 and 6 are supported by a frame 7, which is secured to the base of the apparatus. The upper jewel-bearing 5 is adjustable in the usual manner. Around the lower jewel-bearing 6 is a collet or ring 9, which rests upon the frame 7 and which is free to rotate about said lower jewel-bearing as an axis. Secured to this collet 9 is an arm 9. Secured to this arm 9 is a post 8. The free end of the arm 9 enters a transverse hole in a lug 11, which is pivoted to the car 10. The arm 9 is free to move axially in the hole in said pivoted lug 11.

12 is an involute spring, one end of which is attached to the oscillated shaft 4, and the other end of which is adjustably attached to the post 8. The oscillated shaft 4 carries rigidly secured to it a contact-arm 13. Secured to the frame 7, but insulated from it, are two contacts 14 and 14, with which the contact-arm 13 is capable of making electrical connection as the shaft 4 is oscillated in one direction or the other.

The mechanism for making the record consists of a frame 15, attached to the base of the apparatus. Secured to the frame 15 are guides 16 and 16. This frame also carries a threaded shaft 17, upon which is rigidly mounted an iron driven friction-disk 18. The car 10 travels on the guides 16 and 16, and to it is secured a nut 19, which is threaded to the threaded shaft 17. The threaded shaft 17 is capable of movement in rotation only, and the nut 19 being capable of axial movement only as the threaded shaft 17 is rotated the car 10 will move in one direction or the other on the guides 16 and 16, according to the direction of rotation of the threaded shaft 17.

The means for rotating the threaded shaft 17 in one direction or the other, as may be required, consists of two iron friction-disks 20 and 20, mounted fixedly upon a drivingshaft 21, so that both friction-disks 20 and 20 mayv be turned in the same direction as the driving-shaft. The driving-shaft 21 has axial movement to bring the side of either one of the friction-disks 20 or 20 into action 1 with the periphery of the driven friction-disk 18. The driving-shaft 21 is to be driven at a constant speed by any desirable means-as, for example, a driving-belt 22 working on the pulley 22, connected with any suitable construction of motor. (Not shown.)

The friction-disks are brought into action as follows:

Around the driving-shaft 21, but separate from it, upon a block 23, which is fastened to the base of the apparatus, are two stationary electromagnets 24 and 24. These stationary electromagnets are wound with coils of copper insulated wire. One of the terminals of each electromagnet is connected to a-common conductor leading to one pole of the battery 25. The opposite pole of the battery 25 is connected by a conductor 34 to the contact-arm 13 on the oscillated shaft 4. The other two terminals of the electromagnets 24 and 24 are connected, respectively, by conductors 35 and 36 to the contacts 14 and 14. magnetic circuits of the electromagnets 24 and 24 are through the cast-iron block 23, the portion of the driving-shaft 21 between the disks 20 and 20, the disks themselves, and cast-iron driven friction-disk 18,

26 is the chart, which consists of a long length of paper ribbon or record-sheet having longitudinal lines or rulings which are calibrated to the spring 12. The ribbon or record-sheet 26 is wound upon an inner roller The 27 and held in tension by a spring 28, whic holds the brake-disk 28 against the end of the inner roller 27. A driven outer roller 29 draws the chart or ribbon 26 forward and holds the same wound upon it after the same has been made a record. Impressions are made upon the chart by a pencil or stylus 33, carried by an arm 32, attached to and. moving with the car 10. The longitudinal movement of the ribbon and the transverse movements of the car 10 will determine the curvatures of the record impression made by the stylus.

The chart is given continuous and regular movement in the manner following: Upon the end of the driving-shaft 21 is rigidly mounted a spur-gear 30, which meshes with the gear 31. The spur-gear 30 has SUfl'llCiGIlt width of face to remain in mesh with. the gear 31, whichever of the two disks 20 or 20 are in action. The gear 31 rotates a worm 30, which in turn rotates a gear 31, which in turn rotates a worm 32 .in mesh with the gear The 32 is mounted upon the shaft of the outer roller 29, and consequently motion in rotation is imparted to the outer roller 29 through the reducing-gear just described.

Having thus indicated generally the several parts of my invention and their several relations, I will now describe its operation.

Assume that a small electric motor or other suitable source of power is connected with the belt 22 which passes over the pulley 22 and drives the shaft 21., and. therefore imparts continuous movement to the recordblank by the mechanism just described. Assume also that the series and shunt coils are energized. The interaction of the series and shunt coils when energized upon the secondary element will cause the oscillated shaft 4 to rotate slightly, thus bringing the contact-arm 13 in touch with one of the adjustable contacts 14 or 1.4. Suppose that it is in the contact 14. The circuit thus closed will include the battery 25, wire 34, contact-arm 13, contact 14, wire 35, electromagnet 24:, and thence back to battery through the cornmon return. This will energize the electromagnet 24 and cause it to attract the inner disk 20 and bring its side into frictional action with the periphery of the driven frictiondisk 18. The driving-shaft 21 being in constant rotation, the threaded shaft 1.7 will be rotated and the nut 19 will move the car 10 in the direction to swing the arm 9 in the opposite direction from that in which the secondary element 3 has been rotated. This will cause the secondary element to swing slightly in the direction to break electrical connection between the contact-arm 13 and contact 14. As soon as the circuit just described is broken the car 10 comes to rest, as the electromagnet 24 is no longer energized, and the inner disk 20 is entirely out of frictional contact with the driven friction-disk 18 or has so little friction. that it will not drive it. The carriage will remain at rest so long as the current is constant; but suppose the flow of current changes so as to rotate the secondary element 3 to bring the contactarm 13 into electrical connection with the contact 1 1. This will close a circuit including the battery 25, so that current will flow from battery through wire 341, contact-arm 13, contact 14, wire 36, electromagnct 24, and thence by common return back to the battery. This will energize the electromagnet 24 and cause it to attract the outer disk 20 and bring its side into frictional contact with the peri phory of the driven frictiondisk 18. This will move the car 10 in the opposite direction of travel from that when the SQQOlHltllf element was moved to make electrical connection between the contactarm l3 and the contact 14. In like manner, as above described, the movement of the car will presentl break the connection between the contact-arm 13 and the contact 14, and the car will remain at rest so long as the flow of current is constant. An equilibrium is thus maintained between the tension of the spring and the torque of the meter elements. When the amount of power flowing through the me er elements changes, then the car must take up a new position in order to restore equilibrium.

It will be evident that during the time of action just described the char-t has been moving at a slow but regular speed and that with the variation of load the pencil 33 has made a mark on the chart at an angle to the length of the chart and that while the current was regular and equilibrium was m aintained the pencil has made a mark or line parallel with the length of the record-blank.

As above stated, the chart is calibrated to the particular spring of the wattmeter to which it is applied, the divisions being longitruinal lines the distances between which correspond to definite amounts of power passing through the meter.

Having thus described my invention and its method of operation, what I claim is 1. A wattmeter for measuring alternating currents, comprising a secondary element, an involute spring normally holding an indicator carried by said secondary element at zero, primary and shunt coils arranged to act upon the two wings of said secondary element, mechanism for driving a record -blank at continuous and regular speed, a source of energy for driving said mechanism, a stylus for making a graphic record, a car carrying said. stylus, a nut and a screw for imparting transverse movement to said car, a driven frictiondisk on said screw, a driving-shaft, frictiondisks mounted rigidly thereon, said disks being positioned upon said shaft, and said shaft having axial movement to permit either one or the other of said disks to engage said driven friction-disk diametrically opposite to each other, a source of electric energy, electromagnets mounted between said disks and concentric therewith, electric circuits, contacts for closing said circuits, and a contactarm mounted in rotation with said secondary element for closing one or the other of said circuits of said battery and its respective magnet, according to the direction of rotation of said secondary element, to put-one or the other of said friction-disks in frictional contact with said driven friction-disk to impart motion to said car carrying said stylus in one direction or the other.

2. A wattmeter for measuring alternating currents, comprising a secondary element, an involute spring normally holding an indicator carried by said secondary element at zero, primary and shunt coils arranged to act upon the two wings of said secondary element, mechanism for driving a record-blank at continuous and regular speed, a source of energy for driving said mechanism, a stylus for making a graphic record, a car carrying said stylus, a nut and a screw for imparting transverse movement to said car, a driven frictiondisk on said screw, a driving-shaft, frictiondisks mounted rigidly thereon, said disks being positioned upon said shaft, and said shaft having axial movement to permit either one or the other of said disks to engage said driven friction-disk diametrically opposite to each other, a source of electric energy, electromagnets mounted between said disks and concentric therewith, electric circuits, contacts for closing said circuits, a contact-arm mounted in rotation with said secondary element for closing one or the other of said circuits of said battery and its respective magnet, according to the direction of rotation of said secondary element, to put one or the other of said friction-disks in frictional contact with said driven friction-disk to impart motion to said car carrying said stylus in one direction or the other, an arm pivoted concentrically with said secondary element and its free end slidably secured to said car, whereby said arm is moved over an arc of a circle in one direction or the other according to the movement of said car, a post mounted on said arm and carrying one end of said involute spring of said secondary element, whereby, by the rotation of said post carrying one end of said involute spring, equilibrium of said secondary element is established at any time when the current measured becomes constant in volume.

In testimony whereof I have hereunto set my hand, in the presence of two witnesses, at Buffalo, New York, February 13,1905.

LORIN E. IMLAY.

Witnesses:

JAsoN A. JoHNsoN, THOMAS A. PANTER. 

